Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 05-15-2009, 04:49 PM   #1
Newbie
 
Join Date: May 2009
Posts: 2
Share |
Default

"Uneven" flame on start-up


Hi,

First post here, my name is Rob.

My HVAC unit is a downdraft verticle mounted Bryant Series 80 Model 376CAV048096. Manufacture and install dates are 1999.

The title for lack of a better description is what I am trying to remedy. The unit goes thru a typical heating startup without any other unusual factors. Once it gets to the point of ignitor glowing and gas flowing heres what happens. The flames start to ignite and once flames are present they may faintly "pulse" or have a rough startup. Maybe one jet or another flame is not as "organized" as the others. Within a second or two the flames in all four ports are "organized" and flaming into the box smoothly as they should. It is not one port that has an issue in particular.

I could go as far to say it has a "rough" startup that happens most on the first startup of the evening. Sometimes on the first startup it will not flameup properly and shortcycle yeilding at 34 code which would be consistent with what is occurring. If it goes through maybe 10 to 12 cycles in a cooler evening it with short cycle maybe once and have a noticable uneven startup on one out of three. It is not a very consistent occurence. It makes it even more puzzling.

Okay, with that being said heres what I have done.

Checked the ignitor which appears functional and okay.
Cleaned the flame sensor with 220 sand paper (not visually needing it really)
With compressed air, blew out flame ports for dust debris, etc.
Check for any obstructions in the vent pipe on the top.
Cleaned condensate drains and light water buildup.
Checked filter.
Checked gas valve.
No switches needed reset. All checked.
No multimeter or pressure checks.

What else am i missing here?

Thanks in advance for your insight and comments,
I will reply to acknowledge your help here.

Regards,

Rob
in So Calif.

hvacrob is offline   Reply With Quote
Old 05-15-2009, 05:20 PM   #2
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 9,000
Default

"Uneven" flame on start-up


Remove the burners and check the slots for rust/carbon buildup and the face of the burners also. Your gas valve may be wonky OR the gas pressure to your house may be low. I had one once where the gas co utility regulator was failing/unable to maintain proper pressure, and older gas meters can fail. Would need a tech with a manometer to monitor the pressure on startup.

yuri is online now   Reply With Quote
Old 05-15-2009, 06:36 PM   #3
Newbie
 
Join Date: May 2009
Posts: 2
Default

"Uneven" flame on start-up


Hi Yuri,

Thanks for the fast reply. The four flame ports are clean with no carbon or rust build up at all.

I considered the possiblity of gas valve having some sort of an issue, I think that given the age of my gas meter (not that old) i could almost rule that out.

What about the flame sensor, even though it looks good visually, would it make sense to change it out anyways. Could it be the culprit?

Regards,

Rob
hvacrob is offline   Reply With Quote
Old 05-15-2009, 07:21 PM   #4
HVAC / Plumbing
 
Join Date: Feb 2009
Posts: 1,801
Default

"Uneven" flame on start-up


check pressure at the furnace... I worked for a gas utility once. Sometimes we had reg. malfunction at the meter set. If you can't find any problems. The utility may check their regulator
kenmac is offline   Reply With Quote
Old 05-15-2009, 08:13 PM   #5
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 9,000
Default

"Uneven" flame on start-up


Sounds awful suspicious like their regulator is acting up, as it happens when sitting for awhile.
yuri is online now   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Miller G5RA furnace flame sensor problem mpit52 HVAC 3 01-16-2009 10:30 AM
Brand new PAYNE PG9MAB won't start . Error code 12 tp618 HVAC 3 12-19-2008 09:21 PM
Blue smoke at start up, and shudder at idle fauer Automotive Repairs 6 08-22-2008 11:39 AM
Mower won't start, anything I can try before bringing it to the shop? joeyboy Landscaping & Lawn Care 6 08-05-2008 02:08 PM
Flame blowin' in the wind... testeng HVAC 4 10-28-2007 03:11 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.